On an updated aptosid system, I had no problems installing the released 3.3 Final LibreOffice from here.

It installs in /opt and does not touch your menu (KDE), so it is necessary to use the menu editor to add it manually. Also, I didn't find the icons. I opened a couple of spreadsheets with scalc, and a couple of documents with swriter, and there are no obvious issues at that level.

This system did not previously have OOO installed, so I don't know about that question.

Too bad, just removed the download an hour ago, but this is what i remember:
If you unpack the zip file, go into the directory where you will find all the packages and one folder called 'Desktop Integration', change into that directory, you will find one deb, this is the deb to create the menu for the desktop environment you are using. Install it with